Tray container blanks and tray containers

Abstract

To provide a tray container which does not look like a corner of a bottom surface has an opening and leaves no paper residue.SOLUTION: There is provided a tray container (1) formed from a laminated sheet having a thermoplastic resin layer at least on an inside and using paper as a base material, the tray container including: a polygonal bottom plate (3); a side plate (4) fixed via valley crease lines with each side of the bottom plate peripheral edge as a lower side; a flange (5) fixed to an upper side opposite to a lower side of the side plate via the crease line; and an inclined side plate (43) between the side plates. There is a web corner piece (6) between the side plate and the inclined side plate, with the tip of the web corner piece not touching the bottom plate.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a tray container manufactured from a sheet having a paper base material, which is less likely to cause liquid leakage, especially at corners of the fused surface. [Background technology]

[0002] Conventionally, tray containers made from a paper-based sheet have been produced using a sheet the front and back of which are covered with highly adhesive polyethylene or the like. Tray containers made from paper-based sheets are heat-resistant and insulating, and are easy to carry and move even after heating in a microwave oven, making them easy to use.

[0003] For example, in Patent Document 1, side panels are connected to two opposing sides of a rectangular bottom panel via mountain fold lines, edge pieces are connected to the outer periphery of the side panels via valley fold lines, and tongue pieces extending laterally are provided at the left and right ends of the edge pieces, respectively, and inverted triangular fold-in joint panels are connected to the left and right ends of the side panels via mountain fold lines, and joint edge pieces are connected to the outer periphery of the fold-in joint panels via valley fold lines, and second side panels are connected to the other two opposing sides of the bottom panel via mountain fold lines, and second edge pieces are connected to the outer periphery of the second side panel via valley fold lines, and second tongue pieces extending laterally are provided at the left and right ends of the second edge pieces, respectively, and A second inverted triangular fold-in joint plate is connected to the left and right ends of the side panel via a valley fold line, and the edge of the fold-in joint plate that is not connected to the side panel and the edge of the second fold-in joint plate that is not connected to the second side panel are connected via a mountain fold line, and when the side panels are folded and assembled into a tray shape, the edge piece, second edge piece, and joint edge piece are each configured to form the same plane, and the tray container blank is characterized in that a small protrusion that protrudes toward the second fold-in joint plate is provided on the edge of the second tongue piece near where the second tongue piece at each corner meets the second fold-in joint plate.

[0004] In tray containers manufactured from such tray container blanks, the tongue edges of the edge pieces overlap, creating a double layer, creating a step. In particular, this step is difficult for the base material to change significantly with heat, making it difficult to fuse the lid material evenly, making it difficult to achieve a complete seal. Therefore, a tray container was devised that would not produce steps or gaps when fused by removing the folded-in joint plate portion of the base paper and laminating a sealant layer or the like on the front and back in that state. However, if the joining edge pieces that will be folded in this way are cut out in advance before manufacturing, the parts adjacent to the corners of the bottom surface will be narrow corners, making it easy for pieces of paper to remain. To address this problem of paper remaining, a method was considered in which the parts adjacent to the corners of the bottom surface were cut out with a curved surface with a large R, making it larger. However, in this case, a corner formed only by the resin layer was formed on the side panel near the corner of the bottom, making it look like there was a hole, which caused new problems with appearance and made consumers anxious about leaks. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3687396 Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, an object of the present invention is to provide a tray container that does not appear to have holes in the corners of its bottom surface. [Means for solving the problem]

[0007] The tray container of the present invention is It is formed from a laminated sheet having a thermoplastic resin layer on at least the inner side and a paper substrate, A polygonal bottom plate; Side panels connected to the bottom panel at each bottom edge of the periphery via valley fold lines; a flange that connects the top edge of the side panel opposite the bottom edge via a mountain fold; and web corner pieces that are located between adjacent side panels or adjacent flanges and that bring the end edges of the side panels or flanges into contact with each other, In a tray container formed by folding the web corner pieces along a central web center line extending from the vicinity of each corner of the bottom panel to the periphery and fusing them to the surface of either the left or right side panel or the flange, The tray container is characterized in that the web corner piece has a resin portion without a base material, in which the corner tip formed by the end edges of the adjacent side panels is rounded in an R shape.

[0008] In the process of cutting out the web corner portion of the paper base material of the tray container of the present invention, the corner tip formed by the edge of the adjacent side panel is rounded in an R shape, and the resin portion without the base material is removed from the vicinity of the sharp-angled corner of the bottom surface and processed. Therefore, the corners of the bottom surface of the container are formed by the web corners on the corner side where the substrate is located, so that the tray container does not appear to have holes. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a diagram of a first embodiment showing the shape of a blank used in a tray container of the present invention, and a partially enlarged view thereof. FIG. [Figure 2] This is a diagram showing a form in which the web corner portions of the paper base material that constitutes the blank used in the tray container of the present invention are pre-punched before being laminated with thermoplastic resin layers on the front and back, and an enlarged partial view of that form. [Figure 3] This is a first embodiment of the tray container of the present invention, and includes a plan view of the molded tray container, a cross-sectional view near the flange showing the state of the web corner portion near the corner, a cross-sectional view near the bottom, and a side view of the tray container. [Figure 4] 10A and 10B are diagrams showing a second embodiment of the shape of a blank used in the tray container of the present invention, and a partially enlarged view thereof. [Figure 5] 1A and 1B are diagrams showing an example of the configuration of a laminate sheet used in the tray container of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The tray container of the present invention will be described in detail below with reference to the drawings. FIG. 1-1 is a diagram showing the shape of a blank 2 used in a first embodiment of a tray container of the present invention. The tray container of the present invention has a polygonal bottom plate, but this first embodiment is a tray container having an octagonal bottom plate 3 with the four corners of a rectangle chamfered. The bottom plate 3 has side panels 4 that are connected to each other via valley fold lines along the periphery of the bottom periphery 31 of the bottom plate 3. The side panels 4 are trapezoidal, with the bottom periphery 31 of the bottom plate 3 as the base and the opposite side as the top. The side panel 4 also has a flange 5 attached to the upper edge thereof via a mountain fold.

[0011] Furthermore, the blank 2 has web corner pieces 6 between adjacent side panels 4 or adjacent flanges 5 . Since the resin web corner piece 6 does not have a base material layer, it is thin even when in the form of a laminated sheet, but can be pressed together even thinner when fused.

[0012] FIG. 5 shows an example of the structure of a laminated sheet 20 used in the tray container of the present invention. The laminated sheet is made up of at least an outer thermoplastic resin layer 14 on the outermost surface and a base layer 11 made of paper. and an inner thermoplastic resin layer 12 on the innermost surface. Furthermore, a barrier layer 13 may be included between the base material layer 11 and the inner thermoplastic resin layer 12 via an adhesive layer 15 . At the web corner piece 6 of the laminated sheet 20, the paper base layer is removed, so only the portion of the web corner piece 6 is thin.

[0013] FIG. 1-2 shows an enlarged view of the portion of the web corner piece 6 that contacts the bottom plate 3. The web corner piece 6 is an area surrounded by the inclined side panel 43 and the two left and right side panel 4 end sides. The web corner piece 6 has a rounded tip on the bottom side. Here, the blank 2 in FIG. 1 is the first embodiment, and has a ruled line formed along the boundary between the web corner piece 6 and the inclined side panel 43 from near the tip of the web corner piece 6 toward the side panel.

[0014] FIG. 2 is a diagram showing a state in which a paper substrate constituting a blank used in a first embodiment of the tray container of the present invention has been punched before being laminated with a thermoplastic resin layer. As shown here, the substrate is pre-punched and a thermoplastic resin layer is laminated onto this substrate. When cutting out the web corner piece 6, it is advisable to use a die that uses a rubber or similar tool to forcibly remove the scrap from the die inside the cutting blade at the bottom end. In this case, since the tip is rounded, it is less likely to be cut from the wide outer part, generating scrap. Furthermore, if a punching margin 66 is provided that protrudes a few millimeters from the outer portion of the web corner piece 6 that does not become part of the product, it can be covered even if punching deviation occurs when punching the outer shape.

[0015] Fig. 3 shows a tray container 1 according to a first embodiment of the present invention, which is a tray container formed using the blank shown in Fig. 1. Fig. 3-1 is a plan view, and Fig. 3-2 is a side view. An enlarged cross-sectional view of the overlapping state of the web corner pieces 6 in the vicinity of the flange is added as an AA cross-sectional view. An enlarged cross-sectional view of the web corner portion near the corner of the bottom plate is shown in the B-B cross-sectional view.

[0016] As shown in the plan view, the web corner pieces 6 are pushed inward through the gaps between adjacent side panels or adjacent flanges, and are fused to the inner surfaces of the inclined side panels 43 and the upper surfaces of the flanges 5 .

[0017] The tips of the web corner pieces 6 do not reach the bottom plate 3, but are spaced apart. By molding in this shape, a film appears near the bottom after molding, and the appearance of a hole does not appear.

[0018] Fig. 4 is a diagram of a blank for a tray container 1 according to a second embodiment of the present invention. The laminate sheet used for this tray container has a thermoplastic resin layer and is made of a paper substrate, and is manufactured in the configuration shown in Fig. 5. In the second embodiment, the blank is made by cutting the outline of the laminated sheet into the shape shown in Figure 4 using a knife blade, and a line is formed along the boundary between the web corner piece 6 and the side panel 4, from near the tip of the web corner piece 6 toward the bottom panel 3.

[0019] The tray container of the present invention is as described above. The substrate layer used is a sheet having a basis weight of 150 g / m 2 More than 600g / m 2 The following paper is used: 150 g / m 2 If it is less than 600g / m, it will not have enough strength and will not be able to maintain its shape when contents are placed inside. 2 When using paper with a basis weight of 150 g / m, excessive force is required to create the lines, etc., and the folded parts tend to slip out of place. 2 More than 600g / m 2 The following papers are preferably used: Furthermore, the thermoplastic resin to be laminated onto the substrate can be a resin that has high mutual fusion, such as polypropylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, or ionomer resin. Furthermore, as shown in FIG. 5, a barrier layer 13 may be included between the base material layer 11 and the inner thermoplastic resin layer 12 with an adhesive layer 15 interposed therebetween. The barrier layer 13 can be made of a saponified ethylene-vinyl acetate copolymer, a polyamide resin, or the like. Alternatively, it can be made of a metal foil such as aluminum, or a polyethylene terephthalate film or polyamide film on which a metal oxide such as silicon oxide or a metal such as aluminum is vapor-deposited. These can be manufactured using a tandem extruder laminator or by laminating using a dry lamination machine. [Example]

[0020] Specific examples of the present invention will be described below.

[0021] Example 1 As the paper substrate 2, cup base paper (basis weight 260 g / m 2 ) was prepared and cut out in advance into the shape of the first embodiment shown in FIG. At this time, the R shape provided at the tip of the web corner piece 6 was set to R1.5 mm. A polypropylene resin was extruded to a thickness of 60 μm using an extruder lamination machine onto the inner surface of the base paper from which the web corners had been removed, and laminated to produce a laminated sheet. Here, the blank was made by cutting the laminated sheet into the shape shown in Figure 1 with a knife blade, and creating a line along the boundary between the web corner piece and the inclined side panel from near the tip of the web corner piece toward the bottom panel. Using the above blank, the web corner pieces were fused to the inner surfaces of the inclined side panels to obtain a tray container.

[0022] <Example 2> The configuration was the same as in Example 1, except that the tip shape of the web corner piece was 2.0 mm.

[0023] Example 3 Along the boundary between the web corner piece and the side panel, from the tip of the web corner piece to the bottom panel The configuration was the same as in Example 1, except that a crease was made toward the bottom panel, and no crease was made along the boundary between the web corner piece and the inclined side panel from near the tip of the web corner piece toward the bottom panel.

[0024] Example 4 The configuration was the same as in Example 3, except that the R shape of the tip of the web corner piece was 2.0 mm.

[0025] <Example 5> The configuration was the same as in Example 1, except that the R shape of the tip of the web corner piece was 1.0 mm.

[0026] Example 6 The configuration was the same as in Example 1, except that the R shape of the tip of the web corner piece was 1.2 mm.

[0027] Example 7 Along the boundary between the web corner piece and the inclined side plate, a crease is provided from the vicinity of the tip of the web corner piece toward the bottom plate, and along the boundary between the web corner piece and the side plate, a crease is provided The configuration was the same as in Example 1, except that a ruled line was provided from the vicinity of the tip toward the bottom plate.

[0028] Example 8 The configuration was the same as in Example 1, except that no lines were made along the boundary between the web corner piece and the inclined side panel from near the tip of the web corner piece toward the bottom panel, and no lines were made along the boundary between the web corner piece and the side panel from near the tip of the web corner piece toward the bottom panel.

[0029] <Comparative Example 1> The structure was the same as in Example 1, except that the web corner pieces were formed up to the boundary with the bottom plate.

[0030] <Evaluation method> Ten pieces were prepared for each example and comparative example and evaluated as follows. After box making, the appearance of the tray container was observed, and those that did not show any film near the bottom and did not appear to have holes were marked as "Good", and those that appeared to have holes were marked as "Poor". The presence or absence of cut pieces from the web corners was visually observed using a magnifying glass. Those with cut pieces present were rated "present," and those without cut pieces present were rated "absent." In addition, the appearance was also checked for the presence or absence of wrinkles and cracks.

[0031] <Evaluation results> No scraps from the web corners were found in Examples 1, 2, 3, 4, 7, 8, or Comparative Example 1, but scraps were found in Examples 5 and 6. For this reason, it is preferable that the R of the web corner tip be 1.5 or more. In Examples 1, 2, 3, 4, 7 and Comparative Example 1, no wrinkles or cracks were observed during box making. However, in Example 7, cracks were found in four corners of the web near the corners of the bottom plate, and in Example 8, wrinkles were found in four corners of the web near the corners of the bottom plate. For this reason, it is preferable that the crease from the web corner tip R to the corner of the bottom panel be formed only along either the edge of the side panel or the edge of the inclined side panel. Furthermore, in Examples 1, 2, 3, 4, 5, 6, 7, and 8, no holes appeared to be formed near the corners of the bottom plate. However, in Comparative Example 1, it was confirmed that holes appeared to be present. For this reason, it is preferable to position the web corner tip R away from the corner of the bottom plate. The results are shown in Table 1.

[0032] [Table 1]

[0033] The tray container of the present invention uses a laminated sheet with the base material removed from the web corners except for the area near the corners of the bottom panel, and has a score line cut into only one of the adjacent side panel edges. By making the web corner tips round and positioning them away from the corners of the bottom panel, it does not appear as though there is a hole in the bottom, resulting in a tray container that can be used safely and with peace of mind. By simply changing the shape of the web corners, the appearance of the tray container can be improved and wrinkles and cracks can be prevented. Moreover, this can be achieved by simply changing the blade or press mold, so the present invention has many advantages, such as high productivity and being able to keep product prices low. [Explanation of symbols]

[0034] 1. Tray container 11...Base material layer 12. Inner thermoplastic resin layer 13. Barrier layer 14... Outer thermoplastic resin layer 15...Adhesive layer 2. Blank 3...Bottom version 31. Bottom area 32... Corner of bottom plate 4...Side plate 41...Long side plate 42... Short side plate 43... Slanted side plate 5. Flange 6 Web corner piece 66········

Claims

1. It is formed from a laminated sheet having a thermoplastic resin layer on at least the inner side and a paper substrate layer as a substrate, A polygonal bottom plate; Side panels are connected to the bottom panel via valley fold lines, with each edge of the bottom panel being the lower edge. a flange that is connected to an upper edge of the side panel opposite to the lower edge via a mountain fold; An inclined side panel is provided between the side panels, a web corner piece made of the thermoplastic resin layer not including the paper base layer between the side panel and the inclined side panel; A tray container blank, characterized in that the leading end of the web corner piece does not contact the bottom plate.

2. A blank for a tray container as described in Claim 1, characterized in that the tip of the web corner piece has an R-shape and is cut out in a curve with an R of 1.5 mm or more.

3. 3. A tray container blank according to claim 1, wherein a ruled line is provided along the boundary between the web corner piece and the inclined side panel from near the tip of the web corner piece toward the bottom panel.

4. 3. A tray container blank according to claim 1, wherein a ruled line is provided along the boundary between the web corner piece and the side panel from near the tip of the web corner piece toward the bottom panel.

5. A blank for a tray container as described in any one of claims 1 to 4, characterized in that the bottom plate is octagonal.

6. A tray container characterized in that the web corner piece of the tray container blank described in any one of claims 1 to 5 is extruded from between the side panel and the inclined side panel and welded to the inside of the container.

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